Method and Apparatus for Processing Shared Sub-packets in a Communication System

ABSTRACT

Method and Apparatus for Processing Shared Sub-packets in a Communication System are disclosed. A communication system providing both voice and data services allows for a plurality of subscriber station to share a data sent in a unit of a forward traffic channel. To provide information required by the subscriber stations to determine that a unit of the forward traffic channel is shared, and to correctly decode the data, different control channel structures are described. Additionally, the control channel structures provides for more efficient signaling of code channel assignment.

CLAIM OF PRIORITY UNDER 35 U.S.C. §120

The present Application for Patent is a Continuation of U.S. patentapplication Ser. No. 09/978,425 entitled “Method and Apparatus forProcessing Shared Sub-packets in a Communication System” filed Oct. 15,2001, now allowed, and assigned to the assignee hereof and herebyexpressly incorporated by reference herein.

REFERENCE TO CO-PENDING APPLICATIONS FOR PATENT

The present Application for Patent is related to the followingco-pending U.S. patent application:

“Method and Apparatus for Processing Shared Sub-packets in aCommunication System” having Ser. No. 09/981,027, filed Oct. 15, 2001,assigned to the assignee hereof, and expressly incorporated by referenceherein.

BACKGROUND

1. Field

The present invention relates generally to communication systems, andmore specifically to a method and an apparatus for processing sharedsub-packets in a communication system.

2. Background

Communication systems have been developed to allow transmission ofinformation signals from an origination station to a physically distinctdestination station. In transmitting information signal from theorigination station over a communication channel, the information signalis first converted into a form suitable for efficient transmission overthe communication channel. Conversion, or modulation, of the informationsignal involves varying a parameter of a carrier wave in accordance withthe information signal in such a way that the spectrum of the resultingmodulated carrier is confined within the communication channelbandwidth. At the destination station the original information signal isreplicated from the modulated carrier wave received over thecommunication channel. Such a replication is generally achieved by usingan inverse of the modulation process employed by the originationstation.

Modulation also facilitates multiple-access, i.e., simultaneoustransmission and/or reception, of several signals over a commoncommunication channel. Multiple-access communication systems ofteninclude a plurality of remote subscriber units requiring intermittentservice of relatively short duration rather than continuous access tothe common communication channel. Several multiple-access techniques areknown in the art, such as time division multiple-access (TDMA),frequency division multiple-access (FDMA), and amplitude modulationmultiple-access (AM). Another type of a multiple-access technique is acode division multiple-access (CDMA) spread spectrum system thatconforms to the “TIA/EIA/IS-95 Mobile Station-Base Station CompatibilityStandard for Dual-Mode Wide-Band Spread Spectrum Cellular System,”hereinafter referred to as the TIA/EIA/IS-95 standard. The use of CDMAtechniques in a multiple-access communication system is disclosed inU.S. Pat. No. 4,901,307, entitled “SPREAD SPECTRUM MULTIPLE-ACCESSCOMMUNICATION SYSTEM USING SATELLITE OR TERRESTRIAL REPEATERS,” and U.S.Pat. No. 5,103,459, entitled “SYSTEM AND METHOD FOR GENERATING WAVEFORMSIN A CDMA CELLULAR TELEPHONE SYSTEM,” both assigned to the assignee ofthe present invention.

A multiple-access communication system may be a wireless or wire-lineand may carry voice and/or data. An example of a communication systemcarrying both voice and data is a system in accordance with theTIA/EIA/IS-95 standard, which specifies transmitting voice and data overthe communication channel. A method for transmitting data in codechannel frames of fixed size is described in detail in U.S. Pat. No.5,504,773, entitled “METHOD AND APPARATUS FOR THE FORMATTING OF DATA FORTRANSMISSION”, assigned to the assignee of the present invention. Inaccordance with the TIA/EIA/IS-95 standard, the data or voice ispartitioned into code channel frames that are 20 milliseconds wide withdata rates as high as 14.4 Kbps. Additional examples of a communicationsystems carrying both voice and data comprise communication systemsconforming to the “3rd Generation Partnership Project” (3GPP), embodiedin a set of documents including Document Nos. 3G TS 25.211, 3G TS25.212, 3G TS 25.213, and 3G TS 25.214 (the W-CDMA standard), or“TR-45.5 Physical Layer Standard for cdma2000 Spread Spectrum Systems”(the IS-2000 standard).

An example of a data only communication system is a high data rate (HDR)communication system that conforms to the TIA/EIA/TIA/EIA/IS-895industry standard, hereinafter referred to as the TIA/EIA/IS-895standard. This HDR system is based on a communication system disclosedin co-pending application Ser. No. 08/963,386, entitled “METHOD ANDAPPARATUS FOR HIGH RATE PACKET DATA TRANSMISSION,” filed Nov. 3, 1997,assigned to the assignee of the present invention. The HDR communicationsystem defines a set of data rates, ranging from 38.4 kbps to 2.4 Mbps,at which an access point (AP) may send data to a subscriber station(access terminal, AT). Because the AP is analogous to a base station,the terminology with respect to cells and sectors is the same as withrespect to voice systems.

Existing voice/data communication systems generally utilize voicetraffic channels for conducting voice telephony or data communicationsincluding small file transfer, electronic mail, and facsimile.Consequently, the data transmission rate is limited. For example, in theabove-mentioned communication system in accordance with theTIA/EIA/IS-95 standard provides for establishing multiple trafficchannels, each having a rate of data up to 14.4 kilobits per second.While 14.4 kilobits per second is adequate for the above-mentioned typesof lower data rate applications, the increasing popularity of more dataintensive applications such as worldwide web and video conferencing hascreated a demand for much higher data transmission rates. Thecommunication system in accordance with the TIA/EIA/IS-895 standardsatisfies the data rate requirement, but allows for data transmissiononly. To satisfy the demand for data transmission while retaining voiceservice capability, several communication systems have been proposed.

One such a communication system is the above mentioned communicationsystem in accordance with the W-CDMA standard. Another communicationsystem is described in a proposal submitted by LG Electronics, LSILogic, Lucent Technologies, Nortel Networks, QUALCOMM Incorporated, andSamsung to the 3^(rd) Generation Partnership Project 2 (3GPP2). Theproposal is detailed in documents entitled “Updated Joint Physical LayerProposal for 1xEV-DV,” submitted to 3GPP2 as document numberC50-20010611-009, Jun. 11, 2001, and “Updated Joint Physical LayerProposal for 1xEV-DV,” file L3NQS_Physical_Layer_v09.doc, Aug. 20, 2001,hereinafter referred to as 1xEV-DV proposal. Yet another communicationsystem is described in a proposal to the 3GPP2 submitted by Motorola,Nokia, Texas Instruments, and LSI Logic. The proposal is detailed indocument entitled “1XTREME Physical Layer Specification for IntegratedData and Voice Services in cdma2000 Spread Spectrum Systems,” submittedto 3GPP2 as document number C50-20001204-021, Dec. 8, 2000.

The 1xEV-DV proposal provides an air interface between a plurality ofsubscriber stations and a plurality of subscriber stations enabling asimultaneous voice and data services. For that purpose, the 1xEV-DVproposal defines a set of forward and reverse channels.

The structure of a reverse channels transmitted by a base stations isillustrated in FIG. 1. The reverse Pilot Channel, the Dedicated ControlChannel, and the Fundamental Channel remain unchanged. The SupplementalChannel structure remains unchanged for Radio Configurations 1 through6. The new reverse control channels are the Reverse Rate IndicatorChannel (R-RICH), the Reverse Channel Quality Indicator Channel(R-CQICH), and the Reverse Acknowledgment Channel (R-ACKCH).

The structure of a forward channels transmitted by a base stations104(i) is illustrated in FIG. 2. The Forward Pilot Channel, TransmitDiversity Pilot Channel, Auxiliary Pilot Channel, Auxiliary TransmitDiversity Pilot Channel, Synch Channel, Paging Channel, BroadcastControl Channel, Quick Paging Channel, Common Power Control Channel,Common Assignment Channel, Dedicated Control Channel, ForwardFundamental Channel, Forward Supplemental Channel, and ForwardSupplemental Code Channels are the same as their counterparts in theabove-mentioned IS-2000 standard. The Forward Packet Data Channel, theoptional Forward Primary Packet Data Control Channel, and the ForwardSecondary Packet Data Control Channel are channels defined for 1xEV-DVpacket data operation.

The data services are provided to a subscriber station on a ForwardPacket Data Channel (F-PDCH), which is shared by packet data users basedon time multiplexing. The F-PDCH is composed of a number ofcode-division-multiplexed Walsh sub-channels. The number of sub-channelsvaries in time depending on the demands of the circuit-switched voiceand data users. The F-PDCH structure is illustrated in FIG. 3. Theinformation bit stream 302 to be transmitted is segmented into packetsof several sizes. A 16-bit cyclic redundancy check (CRC) is added toeach packet in block 304, and 6-bit turbo encoder tail allowance isadded in block 306 yielding an encoder packet. In one embodiment, theencoder packets are of sizes 384 bits, 768 bits, 1,536 bits, 2,304 bits,3,072 bits, and 3,840 bits. The encoder packets are encoded by block308. Each encoded packet is then scrambled in blocks 310 by a scramblingpattern generated by block 312 and interleaved by block 314. Some or allof the interleaved symbols are then selected to form sub-packets inblock 316. Depending on the length of the sub-packet, the sub-packetcomprises 1, 2, 4, or 8 slots. In one embodiment, the slot is 1.25 mslong. The sub-packet are QPSK, 8-PSK, or 16-QAM modulated by block 318and demultiplexed into a variable number of pairs (In-phase andQuadrature) of parallel streams by block 320. Each of the parallelstreams is covered with a distinct 32-ary Walsh function by blocks322(i). The Walsh-coded symbols of all the streams are summed togetherto form a single In-phase stream and a single Quadrature stream by block324. The In-phase stream and the Quadrature streams are provided to ablock 326, which adjusts the channel's gain. Several forward linkchannels, both data and voice are then summed in block 328, quadtraturespread in block 330, and the resultant In-phase and Quadrature streamsare baseband filtered in block 332(i), upconverted in blocks 334(i) andsummed in block 336.

The F-PDCH is controlled by a Forward Primary Packet Data ControlChannel (F-PPDCCH) if used and by a Forward Secondary Packet DataControl Channel (F-SPDCCH).

The F-PPDCCH is transmitted during the first slot of F-PDCHtransmissions, and carries a 2-bit field that indicates the F-PDCHsub-packet length. One of ordinary skills in the art recognizes thatbecause the F-PPDCCH carries only information of the F-PDCH sub-packetlength, the use of the F-PPDCCH is optional. The subscriber station mayuse other means for determining the F-PDCH sub-packet length. Thus, forexample, the subscriber station may decode the sub-packet for allsub-packet length hypotheses, and select the most likely one of thehypothesis.

The F-SPDCCH is transmitted over 1, 2, or 4 slots, and the starts of theF-SPDCCH transmissions are aligned with the starts of the correspondingF-PDCH transmissions. The F-SPDCCH carries bits specifying a mediumaccess control (MAC) identifier (ID), the Automatic Repeat reQuest (ARQ)channel ID, the encoder packet size, and the F-PDCH sub-packet ID.

The 1xEV-DV proposal thus allows the base station to send data tomultiple mobiles only on a single slot granularity. Furthermore, thehighest sub- packet data rate that is allowed for 384-bit packets is307.2 kbps with one slot per sub-packet. So even when mobiles arecapable of receiving higher data rates, they are limited to at most307.2 kbps and use at least one slot.

Similarly, the 1XTREME proposal provides an air interface between aplurality of subscriber stations and a plurality of subscriber stationsenabling a simultaneous voice and data services. The 1XTREME proposaluses a fixed sub-packet size of 5 ms for the packet data channels andfor the control channels associated with the packet data channels. Thepacket data sub-packets can be CDM shared, but there is no flexibilityon the duration of the data or control sub-packets. The packet datachannel is controlled with a dedicated CDM channel for each user, calledthe Forward Dedicated Pointer Channel, and with a shared controlchannel, called the Forward Shared Control Channel.

The fixed-duration shared packet data sub-packet and limited control ofthe 1XTREME or 1xEV-DV proposals waste resources and limits the systemthroughput performance. Consequently, there is a need in the art for amethod and an apparatus for improving the throughput of the system byallowing multiple forward-link transmissions per a slot.

SUMMARY

In one aspect of the invention, the above-stated needs are addressed bygenerating a first control channel comprising an indicator that atraffic channel is to be shared and a parameters of a traffic channels;and generating at least one second control channel, each of said atleast one second control channel comprising an identity of at least onesubscriber station and information enabling the subscriber station todemodulate the traffic channel.

In another aspect of the invention, the above-stated needs are addressedby demodulating a first control channel to determine whether a trafficchannel is to be shared; determining a number of subscriber stationssharing a traffic channel and multiplexing of the traffic channel inaccordance with said demodulated control channel if the traffic channelis to be shared; demodulating a second control channel comprisingidentity of a subscriber station, and information enabling a subscriberstation to demodulate a traffic channel; and demodulating the trafficchannel in accordance with said determined multiplexing and the enablinginformation if the acquired identity is identical to an identity of thesubscriber station.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a structure of a reverse channels transmitted by abase stations;

FIG. 2 illustrates a structure of a reverse channels transmitted by abase stations;

FIG. 3 an exemplary forward packet data channel;

FIG. 4 illustrates sub-packet structure in accordance with oneembodiment;

FIG. 5 illustrates sub-packet structure in accordance with oneembodiment;

FIG. 6 illustrates a control channel structure in accordance with oneembodiment;

FIG. 7 illustrates a control channel structure in accordance withanother embodiment;

FIG. 8 illustrates a control channel structure in accordance withanother embodiment;

FIG. 9 illustrates a CDM channel structure in accordance with oneembodiment;

FIG. 10 illustrates a control channel structure in accordance withanother embodiment;

FIG. 11 illustrates a control channel structure in accordance withanother embodiment;

FIG. 12 illustrates a control channel structure in accordance withanother embodiment; and

FIG. 13 illustrates a control channel structure in accordance withanother embodiment.

DETAILED DESCRIPTION Definitions

The word “exemplary” is used exclusively herein to mean “serving as anexample, instance, or illustration.” Any embodiment described herein as“exemplary” is not necessarily to be construed as preferred oradvantageous over other embodiments.

The term packet is used exclusively herein to mean a group of bits,including data (payload) and control elements, arranged into a specificformat. The control elements comprise, e.g., a preamble, a qualitymetric, and others known to one skilled in the art. Quality metriccomprises, e.g., a cyclical redundancy check (CRC), a parity bit, andothers known to one skilled in the art.

The term access network is used exclusively herein to mean a collectionof access points (AP) and one or more access point controllers. Theaccess network transports data packets between multiple access terminals(AT). The access network may be further connected to additional networksoutside the access network, such as a corporate intranet or theInternet, and may transport data packets between each access terminaland such outside networks.

The term base station, referred to herein as an AP in the case of an HDRcommunication system, is used exclusively herein to mean the hardwarewith which subscriber stations communicate. Cell refers to the hardwareor a geographic coverage area, depending on the context in which theterm is used. A sector is a partition of a cell. Because a sector hasthe attributes of a cell, the teachings described in terms of cells arereadily extended to sectors.

The term subscriber station, referred to herein as an AT in the case ofan HDR communication system, is used exclusively herein to mean thehardware with which an access network communicates. An AT may be mobileor stationary. An AT may be any data device that communicates through awireless channel or through a wired channel, for example using fiberoptic or coaxial cables. An AT may further be any of a number of typesof devices including but not limited to PC card, compact flash, externalor internal modem, or wireless or wireline phone. An AT that is in theprocess of establishing an active traffic channel connection with an APis said to be in a connection setup state. An AT that has established anactive traffic channel connection with an AP is called an active AT, andis said to be in a traffic state.

The term communication channel/link is used exclusively herein to mean asingle route over which a signal is transmitted described in terms ofmodulation characteristics and coding, or a single route within theprotocol layers of either the AP or the AT.

The term reverse channel/link is used exclusively herein to mean acommunication channel/link through which the AT sends signals to the AP.

A forward channel/link is used exclusively herein to mean acommunication channel/link through which an AP sends signals to an AT.

The term soft hand-off is used exclusively herein to mean acommunication between a subscriber station and two or more sectors,wherein each sector belongs to a different cell. In the context ofTIA/EIA/IS-95 standard, the reverse link communication is received byboth sectors, and the forward link communication is simultaneouslycarried on the two or more sectors' forward links. In the context of theTIA/EIA/IS-895 standard, data transmission on the forward link isnon-simultaneously carried out between one of the two or more sectorsand the AT.

The term softer hand-off is used exclusively herein to mean acommunication between a subscriber station and two or more sectors,wherein each sector belongs to the same cell. In the context of theTIA/EIA/IS-95 standard, the reverse link communication is received byboth sectors, and the forward link communication is simultaneouslycarried on one of the two or more sectors' forward links. In the contextof the TIA/EIA/IS-895 standard, data transmission on the forward link isnon-simultaneously carried out between one of the two or more sectorsand the AT.

The term re-pointing is used exclusively herein to mean a selection of asector that is a member of an ATs' active list, wherein the sector isdifferent than a currently selected sector.

The term soft/softer hand-off delay is used exclusively herein toindicate the minimum interruption in service that a subscriber stationwould experience following a handoff to another sector. Soft/Softerhandoff delay is determined based on whether the sector, (currently notserving the subscriber station), (non-serving sector) to which thesubscriber station is re-pointing is part of the same cell as thecurrent serving sector. If the non-serving sector is in the same cell asthe serving sector then the softer handoff delay is used, and if thenon-serving sector is in a cell different from the one that the servingsector is part of then the soft-handoff delay is used.

The term non-homogenous soft/softer hand-off delay is used exclusivelyherein to indicate that the soft/softer hand-off delays are sectorspecific and therefore may not uniform across the sectors of an AccessNetwork.

The term credit is used exclusively herein to mean a dimensionlessattribute indicating a quality metric of a reverse link, a qualitymetric of a forward link, or a composite quality metric of both forwardand reverse links.

The term erasure is used exclusively herein to mean failure to recognizea message.

The term outage is used exclusively herein to mean a time intervalduring which the likelihood that a subscriber station will receiveservice is reduced.

The term fixed rate mode is used exclusively herein to mean that aparticular sector transmits a Forward Traffic Channel to the AT at oneparticular rate.

Description

The present invention utilizes the sub-packet structure as defined inthe 1xEV-DV proposal, but further divides the sub-packet granularity.Throughout the following description, the channels are discussed interms of structure required for understanding the concept of theinvention. Consequently, one of ordinary skills in the art appreciatesthat the channel structure may contain additional elements required fortransmission, e.g., CRC, encoder tail bits, and other blocks known toone of ordinary skills in the art.

FIG. 4 illustrates sub-packet structure in accordance with oneembodiment. The sub-packet 400 comprises one or more slots 402(i). Eachof the slots 402(i) is further time-divided into sub-slots 404(i). (Onlyone slot sub-division is shown.) In one embodiment, there are 2, 4 or 8equal sub-slots 404(i).

However, one skilled in the art understands that the sub division is animplementation choice and other sub-divisions are within the scope ofthe invention. The data to a subscriber station are provided in one ormore of the sub-slots 404(i). Each subscriber station can use a numberof sub-slots 404(i), and the number of sub-slots for each of thesubscriber station utilizing each of the sub-packets 402(i) can bedifferent.

In accordance with another embodiment, illustrated in FIG. 5, theslot(s) 502(i) of the sub-packet 500 contain data for several subscriberstations. Data from all the slots 502(i) of the sub-packet 500 for aparticular mobile are sent using one or more of the available Walshchannels. As illustrated in FIG. 5, slots 502(1)-502(n) contain dataencoded by Walsh codes 504(1)-504(m), therefore, carry data for msubscriber stations. Consequently, the number of subscriber stationsreceiving information concurrently may be changed on a sub-packet tosub-packet basis.

Control Structures

Due to the variability of the structure of the F-PDCH as describedabove, a subscriber station must be provided with information enablingthe subscriber station to demodulate the F-PDCH. In one embodimentutilizing the code-division of the sub-packets, the existing structuresof the F-PPDCCH and the F-SPDCCH can be utilized. One skilled in the artappreciates that although the following description describesmodifications of the F-PPDCCH and the F-SPDCCH, this is for tutorialpurposes only, and new channels in accordance with the describedembodiments can be defined. Additional information is carried on one ormore new channels.

FIG. 6 illustrates a control channel structure in accordance with oneembodiment, comprising the F-PPDCCH 600, the F-SPDCCH 602, and one CDMcontrol channel 608(i) for each of the subscriber stations sharing thesub-packet. The F-PPDCCH 600 is utilized as defined in the 1xEV-DVproposal. One of ordinary skills in the art recognizes that because theF-PPDCCH carries only information about the F-PDCH sub-packet length,the use of the F-PPDCCH is optional. The subscriber station may useother means for determining the F-PDCH sub-packet length. Thus, forexample, the subscriber station may decode the sub-packet for allsub-packet length hypotheses, and select the most likely one of thehypothesis.

Similarly, the F-SPDCCH 602 is utilized as defined in the 1xEV-DVproposal with the following modification. One of the values of the MACID of block 604 is reserved to identify that a sub-packet of the F-PDCHis to be shared. In accordance with one embodiment, the MAC ID valueidentifies that the sub-packet is to be shared is all ones. Because allthe subscriber stations for which the shared sub-packets are intendedmust reliably receive the information content of channel 602, channel602 is transmitted at power determined by the power requirement of thesubscriber station, for which the control channel 602 is intended, withthe worst forward link quality metric. Upon receiving the channel 602,each of the subscriber stations demodulates and decodes the MAC ID ofblock 604. If the MAC ID indicates that the sub-packet is for one of thesubscriber stations, the identified subscriber station processes thesub-packet in accordance with the procedures outlined in the 1xEV-DVproposal.

If the MAC ID indicates that the sub-packet is to be shared, theremaining bits of block 606 are interpreted to indicate parameters ofthe shared sub-packet. The parameters comprise a number of subscriberstations sharing the sub-packet. Consequently, each of the subscriberstations acquires this information, and then starts receiving the CDMchannels 608(i). Because each of the CDM channels 608(i) is modulated bya Walsh code, the subscriber stations need to know these Walsh codes. Inone embodiment, pre-determined Walsh codes are reserved for the CDMchannels 608(i). In another embodiment, the subscriber stations arenotified about the Walsh codes by signaling messages. Only the number ofCDM channels 608(i) equal to the number of subscriber stations sharingthe sub-packet is transmitted, and the transmission occurs only when thesub-packet is shared. In one embodiment, the CDM channels 608(i) aretransmitted concurrently, consequently, each of the subscriber stationsaccumulates data from all the CDM channels 608(i), and then postprocesses the accumulated data. Because each of the CDM channels 608(i)is intended for one of the subscriber stations and the base station hasan information about the subscriber station forward link quality metric,the base station transmits each of the CDM channels 608(i) at theminimum power determined by power requirement of the subscriber station.

Each of the CDM channels 608(i) comprises information enabling thesubscriber station to determine which of the CDM channels 608(i) isintended for the subscriber station and information enabling thesubscriber station to demodulate the F-PDCH. The information enablingthe subscriber station to determine which of the CDM channels 608(i) isintended for the subscriber station comprises a MAC ID 610(i). Theinformation enabling the subscriber station to demodulate the F-PDCHcomprises an ARQ ID 612(i), a sub-packet ID 614(i), a packet size616(i), and a number of Walsh channels used 618(i). In one embodiment,the current F-PDCCH coding and modulation is used for each of the CDMchannels 608(i). During the post processing, each of the subscriberstations demodulates the MAC ID 610(i) of a CDM channel 608(i). If theMAC ID 610(i) indicates that the CDM channel 608(i) does not containinformation for the subscriber station, the subscriber station ceasesfurther post processing of the channel and repeats the procedure for thenext CDM channel 608(i+1). If a subscriber demodulates a MAC ID 610(i)indicating that the CDM channel 608(i) contains information for thesubscriber station, the subscriber station demodulates the remaininginformation, and processes the sub-packet on the F-PDCH in accordance tothe gathered information.

In another embodiment utilizing the code-division of the sub-packets,the information is provided on the F-PPDCCH, the F-SPDCCH, and one CDMchannel for all the subscriber stations sharing the sub-packet.Consequently, the F-PPDCCH and the F-SPDCCH have the structure asdescribed with reference to FIG. 6. The structure of the CDM channelcarries the information enabling each of the subscriber stations todemodulate the F-PDCH. The information for all the subscriber stationsis time multiplexed and then encoded and modulated. Consequently, theCDM channel comprises concatenation of the CDM channels 608(i) asdescribed in FIG. 6. In one embodiment, the current F-SPDCCH coding andmodulation is used for the CDM channel. Consequently, the method ofacquiring the information is the same as described above, with theexception that all the subscriber stations demodulate and decode thewhole information carried on the CDM channel. The subscriber stationthen examines the MAC IDs. If the subscriber station fails to find a MACID indicating that the subscriber station is to share the sub-packet,the subscriber station ceases further processing. If a subscriber findsa MAC ID indicating that the following portion of the CDM channelcontains information for the subscriber station, the subscriber stationdemodulates the information, and processes the sub-packet on the F-PDCHin accordance with the gathered information.

One of ordinary skill in the art appreciates that limiting number ofsubscriber station sharing the sub-packet yields further simplificationof the above-described embodiments. Consequently, in one embodimentallowing only two subscriber station to share the sub-packet, theexisting structure of the F-PPDCCH and a modified structure of theF-SPDCCH can be utilized. Thus, there is no need for an additionalcontrol channel.

The F-PPDCCH is utilized as defined in the 1xEV-DV proposal. One ofordinary skills in the art recognizes that because the F-PPDCCH carriesonly information about the F-PDCH sub-packet length, the use of theF-PPDCCH is optional. The subscriber station may use other means fordetermining the F-PDCH sub-packet length. Thus, for example, thesubscriber station may decode the sub-packet for all sub-packet lengthhypotheses, and select the most likely one of the hypothesis.

FIG. 7 illustrates a structure of the modified F-SPDCCH 700. Themodified F-SPDCCH 700 comprises information enabling the two subscriberstations to demodulate the F-PDCH. Therefore, the F-SPDCCH 700 comprisesand MAC IDs for each subscriber stations 702(1), 702(2), ARQ IDs 702(1),704(2), sub-packet IDs 706(1), 706(2), encoder packet sizes 708(1),708(2), and number of Walsh channels used 710(1), 710(2). The structurecan be further simplified if the second subscriber station is assumed touse a number of Walsh channels less than or equal to the number of Walshchannels of the first subscriber station. Then the modified F-SPDCCH 700comprises only one of the blocks 710(1), 710(2).

Because all the subscriber stations intended to share the sub-packetmust reliably receive the modified F-SPDCCH 700, the modified F-SPDCCH700 is transmitted at a power determined by the power requirement of thesubscriber station with the worst forward link quality metric for whichthe modified F-SPDCCH 700 is intended. Upon receiving the modifiedF-SPDCCH 700, each of the subscriber stations demodulates the modifiedF-SPDCCH 700 and decodes the MAC IDs in the blocks 702(1), 702(2). Ifthe MAC ID of the subscriber station is identical to either of thedecoded MAC IDs, the subscriber station acquires the remaininginformation from the modified F-SPDCCH 700, and processes the sub-packetof the F-PDCH in accordance with the information.

The modified F-SPDCCH 700 is transmitted even if the F-PDCH is intendedfor only one subscriber station. In this case, the MAC ID 702(2), isidentical to the MAC ID 702(1). Consequently, the subscriber stationsignore the interpretation of block 704(2) as ARQ ID, 706(2) assub-packet ID, 708(2) as encoder packet size, and 710(2) as number ofWalsh channels used 710(1). Consequently, these blocks can be used forany additional information. The subscriber a MAC ID of which isidentical to the decoded MAC ID acquires the remaining information fromthe modified F-SPDCCH 700, and processes the sub-packet of the F-PDCH inaccordance with procedures outlined in the 1xEV-DV proposal.

In accordance with another embodiment, the existing structures of theF-PPDCCH and the F-SPDCCH can be utilized. The F-PPDCCH is utilized asdefined in the 1xEV-DV proposal. One of ordinary skills in the artrecognizes that because the F-PPDCCH carries only information about theF-PDCH sub-packet length, the use of the F-PPDCCH is optional. Thesubscriber station may use other means for determining the F-PDCHsub-packet length. Thus, for example, the subscriber station may decodethe sub-packet for all sub-packet length hypotheses, and select the mostlikely one of the hypothesis. The F-SPDCCH comprises informationenabling one of the two subscriber stations to demodulate the F-PDCH andan indicator to specify whether another CDM control channel istransmitted. The CDM control channel comprises information enabling onesubscriber station to demodulate the F-PDCH.

FIG. 8 illustrates a control channel structure the F-SPDCCH 800, and theCDM control channel 802. The F-SPDCCH 800 comprises an MAC ID 804, ARQID 806, sub-packet ID 808, encoder packet size 810, and numbers of Walshchannels used 812 for one of the possible two shared channels, and a CDMindicator 814.

The CDM channel 802 comprises an MAC ID 816, ARQ ID 818, sub-packet ID820, encoder packet size 822, and number of Walsh channels used 824 forthe second shared channel if it is used. If the F-PDCH sub-packet is notshared, the CDM channel 802 is not transmitted for that sub-packet

In one embodiment, the F-SPDCCH 800 and, if used, the CDM controlchannel 802 are transmitted concurrently. Because the subscriberstations do not know, whether the CDM control channel 802 is transmittedor not, each of the subscriber stations accumulates data from both theF-SPDCCH 800 and all the CDM channel 802, and then post processes theaccumulated data. Because both subscriber stations to share thesub-packet must reliably receive the F-SPDCCH 800, the F-SPDCCH 800 istransmitted at a power determined by power requirement of the subscriberstation with the worst forward link quality metric fro which theF-SPDCCH 800 is intended. Because the CDM control channel 802 isintended for one of the subscriber stations and the base station has aninformation about the subscriber station's forward link quality metric,the base station transmits the CDM control channel 802 at the minimumpower determined by power requirement of the subscriber station.

Upon receiving the modified F-SPDCCH 800, each of the subscriberstations decodes the MAC ID 804. If the decoded MAC ID is identical tothe subscriber station's MAC ID, the subscriber station decodes theremaining information from the F-SPDCCH 800, and processes thesub-packet of the F-PDCH in accordance with the information.

The subscriber stations, MAC IDs of which are not identical with thedecoded MAC ID, decode the CDM indicator 814. If the CDM indicator 814indicates that no CDM control channel 802 is transmitted, the subscriberstations cease further processing; otherwise the subscriber stationsdecode the MAC ID 816. The subscriber station, a MAC ID of which isidentical with the decoded MAC ID acquires the remaining informationfrom the CDM control channel 802, and processes the sub-packet of theF-PDCH in accordance with the information. The subscriber stations, MACIDs of which are not identical with the decoded MAC ID cease furtherprocessing.

In another embodiment utilizing the time-division of the F-PDCHsub-packets, the control information is provided on the F-PPDCCH, theF-SPDCCH, and one CDM channel for each of the subscriber stationssharing the sub-packet.

The function and the structure of the F-PPDCCH is identical to thefunction and the structure of the F-PPDCCH as described above withregards to the CDM based F-PDCH sub-packet sharing.

Similarly, the function and the structure of the F-PSDCCH is identicalto the function and the structure of the F-PSDCCH as described abovewith regards to the CDM based sub-packet sharing with the followingmodification. If the MAC ID indicates that a sub-packet of the F-PDCH isto be shared, the remaining bits of the F-SPDCCH are interpreted toindicate parameters of the shared sub-packet, which comprise number ofsub-slots into which the sub-packet is subdivided and the number ofsubscriber stations sharing the sub-packet. Consequently, each of thesubscriber stations demodulates the modified F-SPDCCH and decodes theMAC ID. If the MAC ID indicates that the sub-packet is for thesubscriber station, the identified subscriber station processes thesub-packet in accordance to procedures outlined in the 1xEV-DV proposal.

If the MAC ID indicates that the sub-packet is to be shared, thesubscriber stations will use the remaining bits of the F-SPDCCH todetermine the number of sub-slots into which the sub-packet issubdivided and the number of subscriber stations sharing the sub-packet.Consequently, each of the subscriber stations acquires this information,and then starts receiving the CDM channels 900(i), as illustrated inFIG. 9. Because each of the CDM channels 900(i) is modulated by a Walshcode, the subscriber stations need to know these Walsh codes. In oneembodiment, pre-determined Walsh codes are reserved for the CDM channels900(i). In another embodiment, the subscriber stations is notified aboutthe Walsh codes by signaling messages. Only the number of CDM channels900(i) equal to the number of subscriber stations sharing the sub-packetis transmitted, and the transmission occurs only when the sub-packet isshared. In one embodiment, the CDM channels 900(i) are transmittedconcurrently, consequently, each of the subscriber stations accumulatesdata from all the TDM channels 900(i), and then post processes theaccumulated data. Because each of the CDM control channels 900(i) forthe TDM-shared F-PDCH is intended for one of the subscriber stations andthe base station has a information about the subscriber station forwardlink quality metric, the base station transmits each of the CDM controlchannels 900(i) at just enough power to reach the intended subscriberstation reliably.

Each of the CDM control channels 900(i) comprises information enablingthe subscriber station to determine which of the CDM channels 900(i) isintended for the subscriber station and information enabling thesubscriber station to demodulate a F-PDCH. The information enabling thesubscriber station to determine which of the CDM channels 900(i) isintended for the subscriber station comprises a MAC ID 902(i). Theinformation enabling the subscriber station to demodulate the F-PDCHcomprises an ARQ ID 904(i), a sub-packet ID 906(i), a format of theshared sub-packet 908(i), and a starting sub-slot 910(i) for each of themobiles. In one embodiment, the current F-PDCCH coding and modulation isused for each of the CDM channels 900(i). During the post processing,each of the subscriber stations demodulates the MAC ID 902(i) of acontrol channel 900(i). If the MAC ID 902(i) indicates that the controlchannel 900(i) does not contain information for the subscriber station,the subscriber station ceases further post processing of the channel andrepeats the procedure for the next control channel 900(i+1). If asubscriber demodulates a MAC ID 902(i) indicating that the controlchannel 900(i) contains information for the subscriber station, thesubscriber station reads the remaining information, and processes thesub-packet on the F-PDCH in accordance to the gathered information.

In another embodiment utilizing the time-division of the slots, theinformation is provided on the F-PPDCCH, the F-SPDCCH, and one TDMchannel for all the subscriber stations sharing the sub-packet. The TDMchannel is modulated by the information enabling each of the subscriberstations to demodulate the F-PDCH. The information for all thesubscriber station is time multiplexed and then encoded and modulated.Consequently, the CDM channel comprises concatenation of the CDMchannels 900(i) as described in FIG. 9. In one embodiment, the currentF-SPDCCH coding and modulation is used for the CDM channel.Consequently, the method of acquiring the information is the same asdescribed above, with the exception that all the subscriber stationstune to the CDM channel, demodulate and decode the whole information.The subscriber station then examines the MAC IDs. If the subscriberstation fails to find a MAC ID indicating that the subscriber station isto share the sub-packet, the subscriber station ceases furtherprocessing. If a subscriber finds a MAC ID indicating that the followingportion of the CDM channel contains information for the subscriberstation, the subscriber station reads the rest of the information, andprocesses the sub-packet on the F-PDCH in accordance to the gatheredinformation. Furthermore, each of the subscriber stations examines eachportion of the F-SPDCCH containing the information about sub-slotpositions. Consequently, the CDM channel does not need to contain thestarting sub-slot for each subscriber station because the subscriberstations have acquired the information on the duration of sub-slotsintended for the other subscriber stations.

The control channels' structure in accordance with another embodiment isillustrated in FIG. 10. Control channel 1002 comprises an indication ofa number of control channels 1008(i) in block 1004. Furthermore, each ofblocks 1006(i) identifies a MAC ID of a subscriber station for whichinformation is sent on a F-PDCH. To receive the control channel 1002 thesubscriber stations must know modulation parameters of the controlchannel 1002. In one embodiment, the modulation parameters arepre-determined. In another embodiment, the modulation parameters areprovided to the subscriber stations by signaling messages. Because allsubscriber stations must reliably receive the control channel 1002, thecontrol channel 1002 is transmitted at power determined by a powerrequirement of the subscriber station with the worst forward linkquality metric. Upon receiving the control channel 1002, each of thesubscriber stations demodulates and decodes the control channel 1002.Each of the subscriber stations with MAC ID identical to the MAC IDsacquired from block 1006(i) then acquires one of the control channel1008(i). Consequently, the number of the transmitted control channels1008(i) is equal to the number of MAC IDs in the channel 1002. Thesubscriber stations with MAC IDs different from the MAC IDs acquiredfrom block 1006(i) cease further control channel processing.

Each of the additional control channels 1008(i) comprises informationenabling a subscriber station identified by one of the MAC IDs todemodulate the F-PDCH. Therefore, in one embodiment, each of the controlchannels comprises an ARQ channel ID, the encoder packet size, and theF-PDCH sub-packet ID, as well as information for sub-packet TDM/CDMsharing as described above.

To acquire information enabling the subscriber station identified by oneof the MAC IDs in control channel 1002 to demodulate the F-PDCH, theremust exist a relationship between the subscriber station MAC ID and thecontrol channel 1008(i) comprising the information for the subscriberstation. In one embodiment, the relationship is determined by a positionof the blocks 1006(i) within the channel 1002, and an index of the Walshcode encoding the control channel 1008(i). Thus, for example increasingorder of MAC ID position in the control channel 1002 means increasingindex of the Walsh code encoding the control channel 1008(i). Therelationship between the control channel's Walsh code and a MAC ID maybe pre-determined or changeable by signaling messages. However, one ofordinary skills in the art appreciates that other relationships arewithin the scope of the invention. Because each of the additionalcontrol channel 1008(i) is intended for one of the subscriber stationsand the base station has an information about the subscriber stationforward link quality metric, the base station transmits each of thechannels 1008(i) at the minimum power determined by power requirement ofthe subscriber station.

Once a subscriber station demodulates the appropriate control channel1008(i), the subscriber station decodes the information enabling thedemodulation of the F-PDCH, and processes the sub-packet on the F-PDCHin accordance to the gathered information.

The control channel(s) structure in accordance with another embodimentis illustrated in FIG. 11. Each of the control channels 1102(i) containsall the information a subscriber station needs to decode the F-PDCH.Therefore, in one embodiment, each of the channels 1102(i) comprises aMAC ID block 1104, an ARQ channel ID block 1106, the encoder packet sizeblock 1108, and the F-PDCH sub-packet ID block 1110, as well asinformation for sub-packet TDM/CDM sharing as described above,collectively identified as block 1112. Because each of the controlchannels 1102(i) is intended for one of the subscriber stations and thebase station has an information about the subscriber station forwardlink quality metric, the base station transmits each of the channels1108(i) at the minimum power determined by power requirement of thesubscriber station.

To receive the control channels 1102(i) the subscriber stations mustknow modulation parameters of the control channels 1102(i). In oneembodiment, the modulation parameters and the number of possible controlchannels are pre-determined. In one embodiment, the modulationparameters comprise different Walsh codes. Because in accordance withthe embodiment, there is no relationship between one subscriber stationand one control channel 1102(i), the subscriber stations must demodulateall the control channels 1102(i). Although a number of transmittedcontrol channels 1102(i) is equal to a number of subscriber stations forwhich information is send on a F-PDCH because the number of subscriberstations may change in accordance with the granularity of the F-PDCH asdescribed above, the number of transmitted control channels 1102(i)changes.

In one embodiment, the control channels 1108(i) are transmittedconcurrently, consequently, each of the subscriber stations accumulatesdata for all the channels 1108(i), and then post processes theaccumulated data. During the post processing, each of the subscriberstations demodulates one of the control channels 1102(i) and decodes aMAC ID of block 1104(i). The subscriber station with MAC ID identical tothe MAC ID of block 1104(i) demodulates the remaining information, andprocesses the sub-packet on the F-PDCH in accordance to the gatheredinformation. If the MAC ID of block 1104(i) indicates that the channel1108(i) does not contain information for the subscriber station, thesubscriber station ceases further post processing of the channel andrepeats the procedure for the next channel 1108(i). Because asdiscussed, the subscriber station does not have information about thenumber of transmitted control channels 1108(i), unless the subscriberstation finds a MAC ID indicating that the channel 1108(i) containsinformation for the subscriber station, the subscriber station mustattempt to demodulate all possible control channels 1108(i).

The control channel(s) structure in accordance with another embodimentis illustrated in FIG. 12. Each of the control channels 1202(i) containsall the information a subscriber station needs to decode the F-PDCH.Therefore, in one embodiment, each of the channels 1202(i) comprises aMAC ID block 1204, an ARQ channel ID block 1206, the encoder packet sizeblock 1208, and the F-PDCH sub-packet ID block 1210, as well asinformation for sub-packet TDM/CDM sharing as described above,collectively identified as block 1212. In addition, one of the controlchannels 1202(i), e.g., control channel 1202(1) comprises a block 1214,which identifies number of transmitted control channels 1202(i). Becauseit is desirable that all subscriber stations receive reliably theinformation content of the control channel 1202(1), in one embodimentthe control channel 1202(1) is transmitted at power determined by powerrequirement of the subscriber station with the worst forward linkquality metric. Because each of the control channels 1202(2)-1202(m) isintended for one of the subscriber stations and the base station has aninformation about the subscriber station forward link quality metric,the base station transmits each of the channels 1202(2)-1202(m) at theminimum power determined by power requirement of the subscriber station.

To receive the control channels 1202(i) the subscriber stations mustknow modulation parameters of the control channels 1202(i). In oneembodiment, the modulation parameters and the number of possible controlchannels are pre-determined. Furthermore, there exists a relationshipbetween the control channels 1202(i) and the modulation parameters. Inone embodiment, the modulation parameters comprise different Walshcodes, and the transmitted control channels 1202(i) are encoded by Walshcodes with sequential indexes. However, one of ordinary skill in the artappreciates that other relationships are within the scope of theinvention. Because in accordance with the embodiment, there is norelationship between one subscriber station and one control channel1202(i), the subscriber stations must demodulate all the transmittedcontrol channels 1202(i). Although a number of transmitted controlchannels 1202(i) is equal to a number of subscriber stations for whichinformation is send on a F-PDCH because the number of subscriberstations may change in accordance with the granularity of the F-PDCH asdescribed above, the number of transmitted control channels 1202(i)changes.

In one embodiment, the channels 1202(i) are transmitted concurrently,consequently, each of the subscriber stations accumulates data from allthe channels 1202(i), and then post processes the accumulated data.During the post processing, each of the subscriber stations firstdemodulates the control channel 1202(1) and decodes a MAC ID of block1204. The subscriber station with MAC ID identical to the MAC ID ofblock 1204 decodes the remaining information, and processes thesub-packet on the F-PDCH in accordance with the gathered information.The subscriber stations whose MAC IDs are not identical to the MAC ID ofblock 1204 decode the number of transmitted control channels 1202(i) ofblock 1214, cease further post processing of the control channel1202(1), and repeat the procedure for the next channel 1202(i).Therefore, the subscriber stations have information about the number oftransmitted control channels 1202(i). Because as discussed there existsa relationship between the number of transmitted control channels1202(i), unless the subscriber station finds a MAC ID indicating thatthe channel 1202(i) contains information for the subscriber station, thesubscriber station attempts to demodulate only the transmitted channels1202(i).

The control channel structure in accordance with another embodiment isidentical to the control channel structure as illustrated in FIG. 12,with the exception of the relationship between the control channels1202(i) and the modulation parameters. As explained above, it isdesirable that all subscriber stations receive reliably the informationcontent of the control channel 1202(1), in one embodiment the controlchannel 1202(1) is transmitted at power determined by power requirementof the subscriber station with the worst forward link quality metric.Furthermore, each of the control channels 1202(2)-1202(m) is intendedfor one of the subscriber stations and the base station has aninformation about the subscriber station forward link quality metric,consequently, the base station transmits each of the channels1202(2)-1202(m) at the minimum power determined by power requirement ofthe subscriber station. The transmitted control channels 1202(i) areordered in accordance with the transmit power, and are modulated by anordered set of modulation parameters. In one embodiment, the modulationparameters comprise different Walsh codes, and the control channel1202(i) are encoded by Walsh codes with increasing indexes in relationto the increasing transmit power. However, one of ordinary skills in theart appreciates that other relationships are within the scope of theinvention.

In one embodiment, the channels 1202(i) are transmitted concurrently,consequently, each of the subscriber stations accumulates data from allthe channels 1202(i), and then post processes the accumulated data.During the post processing, each of the subscriber stations firstdemodulates the control channel 1202(1) and decodes a MAC ID of block1204. The subscriber station with MAC ID identical to the MAC ID ofblock 1204 decodes the remaining information, and processes thesub-packet on the F-PDCH in accordance with the gathered information.

The subscriber stations whose MAC IDs are not identical to the MAC ID ofblock 1204 decode the number of transmitted control channels 1202(i) ofblock 1214, cease further post processing of the control channel1202(1), and determine the control channel 1202(2)-1202(m) to bedemodulated next. Because of the above-described relationship betweenthe control channel's 1202(i) power and index of the Walsh code by whichthe control channel's 1202(i) is encoded, when a subscriber stationattempts to decode one of the control channels 1202(2)-1202(m) and thedecoding fails, then the subscriber station knows that decoding of anyof the channels 1202(2)-1202(m) sent at lower power is likely to failtoo. Consequently, the subscriber station next attempts to decode one ofthe control channels 1202(2)-1202(m) sent at a higher power. Therefore,one of ordinary skills in the art appreciates that any determinationmethod based on ordered set may be used.

For example, in accordance with one embodiment, the determination methodmay utilize binary search method. If the subscriber station experiencesthe forward link with a good quality metric, the subscriber stationdemodulates the control channel with the lowest power 1202(m), thusencoded by Walsh code with the highest index m. If the decoding fails,the subscriber station repeats the process with the control channel withthe medium power 1202(m/2), thus encoded by Walsh code with the indexm/2. If the decoding is successful, but the MAC ID indicates that thecontrol channel 1202(m/2) does not contain information for thesubscriber station, the subscriber station repeats the process with acontrol channel between 1202(m/2) and 1202(m). The method is repeateduntil the subscriber station exhaust all the control channels between1202(m/2) and 1202(m), or finds a control channel 1202(i) with MAC IDindicating that the control channel 1202(i) is intended for thesubscriber station.

In another embodiment, the subscriber station whose MAC ID is notidentical to the MAC ID of block 1204 measure the power of the controlchannel 1202(i) from the range 1202(2)-1202(m). If the measured power ishigher than the power required by the subscriber station, the controlchannel 1202(i) containing the information for the subscriber station islikely in the range 1202(i)-1202(m). The subscriber station can continuemeasuring the power, using any determination method, e.g., theabove-described binary search or select a control channel from thedetermined range and attempt a demodulation.

The control channel structure in accordance with another embodiment isidentical to the control channel structure as illustrated in FIG. 12,with the exception of the relationship between the control channels1202(i) and the modulation parameters. In accordance with theembodiment, the transmitted control channels 1202(i) are ordered inaccordance with the value of MAC IDs in block 1204, and are modulated byan ordered set of modulation parameters. In one embodiment, themodulation parameters comprise different Walsh codes, and the controlchannel 1202(i) are encoded by Walsh codes with increasing indexes inrelation to the increasing value of MAC IDs in block 1204. However, oneof ordinary skills in the art appreciates that other relationships arewithin the scope of the invention.

Consequently, a subscriber station may use ant determination methodapplicable for ordered set, e.g., one of the above-described methods.

The control channel(s) structure in accordance with another embodimentis illustrated in FIG. 13. Each of the control channels 1302(i) containsall the information a subscriber station needs to decode the F-PDCH.Therefore, in one embodiment, each of the channels 1302(i) comprises aMAC ID block 1306(i) identifying a subscriber station for which thechannel 1302(i) is intended, a partial MAC ID block 1308(i) identifyingsubscriber stations for which another control channel 1302(i) isintended, and information block 1310(i), enabling a subscriber stationidentified by the MAC ID of block 1306(i) to demodulate the F-PDCH. Inaddition, one of the control channels 1302(i), e.g., a control channel1302(1) comprises a block 1304 identifying number of control channels1302(i). The identification of partial MAC ID is an implementationissue. In one embodiment, the MAC ID is expressed as an 8-bit number.Therefore, a subset of the bits identifies a partial MAC ID. In oneembodiment, the subset comprises the most significant bits of a MAC ID.

To receive the control channels 1302(i) the subscriber stations mustknow modulation parameters of the control channels 1302(i). In oneembodiment, the modulation parameters and the number of possible controlchannels are pre-determined. In one embodiment, the modulationparameters comprise different Walsh codes. However, one of ordinaryskills in the art appreciates that other relationships are within thescope of the invention. Furthermore, there exists a relationship betweenthe control channels 1302(2)-1302(m) and the partial MAC IDs. Therelationship is determined by a method the subscriber stations with MACID matching the partial MAC ID a control channel 1302(i) use to selectthe next control channel 1302(i) to demodulate. One of ordinary skillsin the art appreciates that such a method, consequently, therelationships is an implementation issue. In accordance with oneembodiment, the partial MAC ID from block 1308(i) of channel 1302(i)identifies a control channel 1302(m-i-1).

Because all subscriber stations must reliably receive the controlchannel 1302(1), the control channel 1302(1) is transmitted at powerdetermined by power requirement of the subscriber station with the worstforward link quality metric. Because each of the control channels1302(2)-1302(m) are intended for one of the subscriber stations and thebase station has an information about the subscriber station forwardlink quality metric, the base station transmits each of the channels1302(2)-1302(m) at the minimum power determined by power requirement ofthe subscriber station.

In one embodiment, the control channels 1302(i) are transmittedconcurrently, consequently, each of the subscriber stations accumulatesdata from all the channels 1302(i), and then post processes theaccumulated data. During the post processing, each of the subscriberstations first demodulates the control channel 1302(1) and decodes a MACID of block 1306(1). The subscriber station with MAC ID identical to theMAC ID of block 1306(1) decodes the remaining information, and processesthe sub-packet on the F-PDCH in accordance with the gatheredinformation.

If the block 1304 indicates that there are no additional controlchannels 1302(i), the determination method ends.

If the block 1304 indicates that there are m additional control channels1302(i), the determination proceeds as follows.

The subscriber stations with MAC ID matching the partial MAC ID of block1308(1) demodulate and decode the control channel 1302(m), to acquirethe MAC ID of block 1306(m). The subscriber station with MAC IDidentical to the MAC ID of block 1306(m) demodulates and decodes theremaining information of the control channel 1302(m), and processes thesub-packet on the F-PDCH in accordance to the gathered information. Thesubscriber station with MAC ID not matching the MAC ID of block 1306(m)demodulates the next control channel 1302(2) as described below. Sincethe subscriber station has already processed the control channel1302(m), the subscriber station continuing processing and encounteringcontrol channel 1302(m) can cease further processing.

The subscriber stations with MAC ID not matching the partial MAC ID ofblock 1308(1) demodulate the next control channel 1302(i), i.e., thecontrol channel 1302(2). The subscriber station with MAC ID identical tothe MAC ID of block 1306(2) decodes the remaining information of thecontrol channel 1302(2), and processes the sub-packet on the F-PDCH inaccordance to the gathered information. The subscriber stations with MACID matching the partial MAC ID of block 1308(2) follow the processing asoutlined with respect to MAC ID in block 1308. (Thus, the subscriberstations demodulate and decode the control channel 1308(m-1), to acquirethe MAC ID of block 1306(m-1)).

The method is repeated until the subscriber station exhaust all thecontrol channels 1302(i), or finds a control channel 1302(i) with MAC IDindicating that the control channel 1302(i) is intended for thesubscriber station.

Code Channel Assignment Signaling

As discussed, the control channel structure of the invention may utilizethe control channels of the 1xEV-DV proposal, according to theabove-described embodiment. Consequently, the control channel structureof the invention must preserve or improve the functionality of thecontrol channels of the 1xEV-DV proposal.

In accordance to the 1xEV-DV proposal, the F-PDCH sub-packetde-multiplexed into a variable number of pairs (In-phase and Quadrature)of parallel streams, and each of the parallel streams is covered with adistinct 32-ary Walsh code. The F-PDCH Walsh codes are assigned from aWalsh Space List of 28 possible assignments, starting from the top ofthis list. TABLE 1 Default F-PDCH Walsh Space List 32-ary Walsh Codes 3115 23 7 27 11 19 3 29 13 21 5 25 9 30 14 22 6 26 10 18 2 28 12 20 4 24 8

When using the F-PDCH the Walsh code assignment for the F-PPDCCH,F-SPDCCH, and the F-PDCH. Furthermore, for the F-PDCH, number of suchcodes and the Walsh assignments of such codes are required. The numberof Walsh codes in use for the F-PDCH is transmitted on the F-SPDCCH. Asystem and a method for signaling the Walsh space assignment isdisclosed in co-pending application Ser. No. 60/297,105 entitled“HANDLING THE WALSH SPACE INDICATOR FOR 1XEV-DV,” filed Jun. 7, 2001,and assigned to the assignee of the present invention.

In accordance with one embodiment of the present invention, the Walshspace is assigned in accordance with a power of the F-SPDCCH. In oneembodiment, the assignment starts with a highest power F-SPDCCH and thelowest Walsh space. Accordingly, the lowest portion of the Walsh spaceis assigned by the highest power F-SPDCCH, the next lower portion of theWalsh space is assigned by the second highest power F-PDCH, until allthe F-SPDCCH are exhausted. To save power and capacity of the F-SPDCCH,instead of listing the individual Walsh code indexes, each in theF-SPDCCH comprises the number of Walsh codes used.

For example, referring to Table 1, if the highest power F-SPDCCH assignsthe Walsh space comprising the Walsh codes with indexes 31, 15, 23, 7,27, and 11, the highest power F-SPDCCH comprises the number 6, which isthe number of Walsh codes. Similarly, if the second highest powerF-SPDCCH assigns the Walsh space comprising the Walsh codes with indexes19, 3, 29, 13, 21, 5, 25, the second highest power F-SPDCCH comprisesthe number 6.

The subscriber station processes the plurality of F-SPDCCHs inaccordance with the above-disclosed embodiments, to obtain the number ofWalsh codes from each of the plurality of the F-SPDCCHs. The subscriberstation further measures power of each of the plurality of the F-SPDCCH,and orders the obtained numbers of Walsh codes with the measured power.Because the subscriber station is provided with the Walsh Space List,the subscriber station can associate each of the obtained number ofWalsh codes with the Walsh codes.

Those of skill in the art would understand that information and signalsmay be represented using any of a variety of different technologies andtechniques. For example, data, instructions, commands, information,signals, bits, symbols, and chips that may be referenced throughout theabove description may be represented by voltages, currents,electromagnetic waves, magnetic fields or particles, optical fields orparticles, or any combination thereof.

Those of skill would further appreciate that the various illustrativelogical blocks, modules, circuits, and algorithm steps described inconnection with the embodiments disclosed herein may be implemented aselectronic hardware, computer software, or combinations of both. Toclearly illustrate this interchangeability of hardware and software,various illustrative components, blocks, modules, circuits, and stepshave been described above generally in terms of their functionality.Whether such functionality is implemented as hardware or softwaredepends upon the particular application and design constraints imposedon the overall system. Skilled artisans may implement the describedfunctionality in varying ways for each particular application, but suchimplementation decisions should not be interpreted as causing adeparture from the scope of the present invention.

The various illustrative logical blocks, modules, and circuits describedin connection with the embodiments disclosed herein may be implementedor performed with a general purpose processor, a digital signalprocessor (DSP), an application specific integrated circuit (ASIC), afield programmable gate array (FPGA) or other programmable logic device,discrete gate or transistor logic, discrete hardware components, or anycombination thereof designed to perform the functions described herein.A general purpose processor may be a microprocessor, but in thealternative, the processor may be any conventional processor,controller, microcontroller, or state machine. A processor may also beimplemented as a combination of computing devices, e.g., a combinationof a DSP and a microprocessor, a plurality of microprocessors, one ormore microprocessors in conjunction with a DSP core, or any other suchconfiguration.

The steps of a method or algorithm described in connection with theembodiments disclosed herein may be embodied directly in hardware, in asoftware module executed by a processor, or in a combination of the two.A software module may reside in RAM memory, flash memory, ROM memory,EPROM memory, EEPROM memory, registers, hard disk, a removable disk, aCD-ROM, or any other form of storage medium known in the art. Anexemplary storage medium is coupled to the processor such the processorcan read information from, and write information to, the storage medium.In the alternative, the storage medium may be integral to the processor.The processor and the storage medium may reside in an ASIC. The ASIC mayreside in a user terminal. In the alternative, the processor and thestorage medium may reside as discrete components in a user terminal.

The previous description of the disclosed embodiments is provided toenable any person skilled in the art to make or use the presentinvention. Various modifications to these embodiments will be readilyapparent to those skilled in the art, and the generic principles definedherein may be applied to other embodiments without departing from thespirit or scope of the invention. Thus, the present invention is notintended to be limited to the embodiments shown herein but is to beaccorded the widest scope consistent with the principles and novelfeatures disclosed herein.

A portion of the disclosure of this patent document contains material,which is subject to copyright protection. The copyright owner has noobjection to the facsimile reproduction by anyone of the patent documentor the patent disclosure, as it appears in the Patent and TrademarkOffice patent file or records, but otherwise reserves all copyrightrights whatsoever.

1. An apparatus for processing shared sub-packets in a communicationsystem, the apparatus comprising: means for generating a first controlchannel comprising an identity of at least one subscriber station and anumber of second control channels; and means for generating at least onesecond control channel comprising information enabling the at least onesubscriber station to demodulate a traffic channel.
 2. The apparatus asclaimed in claim 1, wherein said means for generating at least onesecond control channel comprising information enabling the at least onesubscriber station to demodulate a traffic channel comprises: means forgenerating at least one second control channel comprising a number ofcode channels encoding a unit of the traffic channel.
 3. The apparatusas claimed in claim 1, wherein said means for generating at least onesecond control channel comprising information enabling the at least onesubscriber station to demodulate a traffic channel comprises: means forgenerating at least one second control channel comprising a number ofsub-divisions and a starting sub-division of a unit of the trafficchannel.
 4. The apparatus as claimed in claim 1, further comprising:means for transmitting the first control channel at a power required bya subscriber station with the worst forward link quality metric forwhich the first control channel is intended.
 5. The apparatus as claimedin claim 1, further comprising: means for transmitting the at least onesecond control channel at a power required by the at least onesubscriber station for which the at least one second control channel isintended.
 6. A method for processing shared sub-packets at a subscriberstation, the method comprising: demodulating a first control channelcomprising an identity of at least one subscriber station and a numberof control channels; demodulating a second control channel comprisinginformation enabling a subscriber station to demodulate a trafficchannel if the identity is identical to an identity of the subscriberstation; and demodulating the traffic channel in accordance with saidenabling information.
 7. The method as claimed in claim 6, wherein saiddemodulating a first control channel comprising identity of a subscriberstation comprises: demodulating a pre-determined control channel.
 8. Themethod as claimed in claim 6, wherein said demodulating a second controlchannel comprising information enabling a subscriber station todemodulate a traffic channel if the identity is identical to an identityof the subscriber station comprises: determining position of theidentity within the received first control channel; selecting a secondcontrol channel in accordance with said determined position; anddemodulating said selected second control channel.
 9. The method asclaimed in claim 8, wherein said selecting a second control channel inaccordance with said determined position comprises: establishing a codeencoding a second control channel in accordance with a relationshipbetween said determined position and the code; and demodulate the secondcontrol channel encoded by said established code.
 10. The method asclaimed in claim 6, wherein said demodulating the traffic channel inaccordance with said enabling information comprises: determining a sizeof traffic channel unit and a number of code channels in accordance withthe enabling information if the traffic channel unit is codemultiplexed; and demodulate the traffic channel unit.
 11. The method asclaimed in claim 6, wherein said demodulating the traffic channel inaccordance with said acquired enabling information comprises:determining a number of sub-divisions of traffic channel unit and astarting sub-division in accordance with the enabling information if thetraffic channel unit is time multiplexed; and demodulate the trafficchannel unit.
 12. A method for processing shared sub-packets in acommunication system, the method comprising: generating a first controlchannel comprising an identity of at least one subscriber station and anumber of second control channels; generating at least one secondcontrol channel comprising information enabling the at least onesubscriber station to demodulate a traffic channel; transmitting thecontrol channels: demodulating the received first control channel;determining an identity of at least one subscriber station and a numberof second control channels in accordance with said demodulated firstcontrol channel; demodulating a second control channel comprisinginformation enabling a subscriber station to demodulate a trafficchannel if the identity is identical to an identity of the subscriberstation; and demodulating the traffic channel in accordance with saidenabling information.
 13. The method as claimed in claim 12, whereinsaid generating at least one second control channel comprisinginformation enabling the at least one subscriber station to demodulate atraffic channel comprises: generating at least one second controlchannel comprising a number of code channels encoding a unit of thetraffic channel.
 14. The method as claimed in claim 12, wherein saidgenerating at least one second control channel comprising informationenabling the at least one subscriber station to demodulate a trafficchannel comprises: generating at least one second control channelcomprising a number of sub-divisions and a starting sub-division of aunit of the traffic channel.
 15. The method as claimed in claim 12,wherein said transmitting the control channels comprises: transmittingthe first control channel at a power required by a subscriber stationwith the worst forward link quality metric for which the first controlchannel is intended.
 16. The method as claimed in claim 15, furthercomprising: transmitting the at least one second control channel at apower required by the at least one subscriber station for which the atleast one second control channel is intended.
 17. The method as claimedin claim 12, wherein said demodulating the received first controlchannel comprises: demodulating a pre-determined control channel. 18.The method as claimed in claim 12, wherein said demodulating a secondcontrol channel comprising information enabling a subscriber station todemodulate a traffic channel if the identity is identical to an identityof the subscriber station comprises: determining position of theidentity within the received first control channel; selecting a secondcontrol channel in accordance with said determined position; anddemodulating said selected second control channel.
 19. The method asclaimed in claim 18, wherein said selecting a second control channel inaccordance with said determined position comprises: establishing a codeencoding a second control channel in accordance with a relationshipbetween said determined position and the code; and demodulate the secondcontrol channel encoded by said established code.
 20. The method asclaimed in claim 12, wherein said demodulating the traffic channel inaccordance with said enabling information comprises: determining a sizeof traffic channel unit and a number of code channels in accordance withthe enabling information if the traffic channel unit is codemultiplexed; and demodulate the traffic channel unit.
 21. The method asclaimed in claim 12, wherein said demodulating the traffic channel inaccordance with said acquired enabling information comprises:determining a number of sub-divisions of traffic channel unit and astarting sub-division in accordance with the enabling information if thetraffic channel unit is time multiplexed; and demodulate the trafficchannel unit.
 22. An apparatus for processing shared sub-packets at asubscriber station, the apparatus comprising: means for demodulating afirst control channel comprising an identity of at least one subscriberstation and a number of control channels; means for demodulating asecond control channel comprising information enabling a subscriberstation to demodulate a traffic channel if the identity is identical toan identity of the subscriber station; and means for demodulating thetraffic channel in accordance with said enabling information.
 23. Theapparatus as claimed in claim 22, wherein said means for demodulating afirst control channel comprising identity of a subscriber stationcomprises: means for demodulating a pre-determined control channel. 24.The apparatus as claimed in claim 22, wherein said means fordemodulating a second control channel comprising information enabling asubscriber station to demodulate a traffic channel if the identity isidentical to an identity of the subscriber station comprises: means fordetermining position of the identity within the received first controlchannel; means for selecting a second control channel in accordance withsaid determined position; and means for demodulating said selectedsecond control channel.
 25. The apparatus as claimed in claim 24,wherein said means for selecting a second control channel in accordancewith said determined position comprises: means for establishing a codeencoding a second control channel in accordance with a relationshipbetween said determined position and the code; and means fordemodulating the second control channel encoded by said establishedcode.
 26. The apparatus as claimed in claim 22, wherein said means fordemodulating the traffic channel in accordance with said enablinginformation comprises: means for determining a size of traffic channelunit and a number of code channels in accordance with the enablinginformation if the traffic channel unit is code multiplexed; and meansfor demodulating the traffic channel unit.
 27. The apparatus as claimedin claim 22, wherein said means for demodulating the traffic channel inaccordance with said acquired enabling information comprises: Means fordetermining a number of sub-divisions of traffic channel unit and astarting sub-division in accordance with the enabling information if thetraffic channel unit is time multiplexed; and means for demodulating thetraffic channel unit.
 28. A apparatus for processing shared sub-packetsin a communication system, the apparatus comprising: means forgenerating a first control channel comprising an identity of at leastone subscriber station and a number of second control channels; meansfor generating at least one second control channel comprisinginformation enabling the at least one subscriber station to demodulate atraffic channel; means for transmitting the control channels: means fordemodulating the received first control channel; means for determiningan identity of at least one subscriber station and a number of secondcontrol channels in accordance with said demodulated first controlchannel; means for demodulating a second control channel comprisinginformation enabling a subscriber station to demodulate a trafficchannel if the identity is identical to an identity of the subscriberstation; and means for demodulating the traffic channel in accordancewith said enabling information.
 29. The apparatus as claimed in claim28, wherein said means for generating at least one second controlchannel comprising information enabling the at least one subscriberstation to demodulate a traffic channel comprises: means for generatingat least one second control channel comprising a number of code channelsencoding a unit of the traffic channel.
 30. The apparatus as claimed inclaim 28, wherein said means for generating at least one second controlchannel comprising information enabling the at least one subscriberstation to demodulate a traffic channel comprises: means for generatingat least one second control channel comprising a number of sub-divisionsand a starting sub-division of a unit of the traffic channel.
 31. Theapparatus as claimed in claim 28, wherein said means for transmittingthe control channels comprises: means for transmitting the first controlchannel at a power required by a subscriber station with the worstforward link quality metric for which the first control channel isintended.
 32. The apparatus as claimed in claim 31, further comprising:means for transmitting the at least one second control channel at apower required by the at least one subscriber station for which the atleast one second control channel is intended.
 33. The apparatus asclaimed in claim 28, wherein said means for demodulating the receivedfirst control channel comprises: means for demodulating a pre-determinedcontrol channel.
 34. The apparatus as claimed in claim 28, wherein saidmeans for demodulating a second control channel comprising informationenabling a subscriber station to demodulate a traffic channel if theidentity is identical to an identity of the subscriber stationcomprises: means for determining position of the identity within thereceived first control channel; means for selecting a second controlchannel in accordance with said determined position; and means fordemodulating said selected second control channel.
 35. The apparatus asclaimed in claim 34, wherein said means for selecting a second controlchannel in accordance with said determined position comprises: means forestablishing a code encoding a second control channel in accordance witha relationship between said determined position and the code; and meansfor demodulating the second control channel encoded by said establishedcode.
 36. The apparatus as claimed in claim 28, wherein said means fordemodulating the traffic channel in accordance with said enablinginformation comprises: means for determining a size of traffic channelunit and a number of code channels in accordance with the enablinginformation if the traffic channel unit is code multiplexed; and meansfor demodulating the traffic channel unit.
 37. The apparatus as claimedin claim 28, wherein said means for demodulating the traffic channel inaccordance with said acquired enabling information comprises: means fordetermining a number of sub-divisions of traffic channel unit and astarting sub-division in accordance with the enabling information if thetraffic channel unit is time multiplexed; and means for demodulating thetraffic channel unit.